Impaired bank loans continue to wind down and have reached a level similar to the industry's starting point at the onset of the GFC six years ago.Impaired loans were $21.6 billion at March 2014, a decrease of $4.7 billion, or 18 per cent, on March 2013, the Australian Prudential Regulation Authority said.Property loans are fading as a concern. Problem commercial property loans are down 40 per cent over the last year.